LED-emitted blue light improves quality of life and reduces fatigue after COVID-19 infection

Introduction: Despite multiple clinical presentations of long COVID, the most common symptom encountered by the patients is fatigue which significantly impacts daily functioning and quality of life. There are, however, multiple unanswered questions regarding the treatment of fatigue among long COVID patients. Several studies highlighted that repetitive exposure to blue light may alleviate the fatigue in different groups of patients but the studies on the efficacy of blue light therapy in treatment of fatigue in long COVID patients are lacking. Aim: To evaluate the effects of blue light therapy in treatment of fatigue among COVID-19 survivors. Material and methods: The study comprised of 43 adults who underwent COVID-19 infection with a subjective feeling of fatigue 4 weeks after the infection. All participants underwent 10 full-body blue light irradiation for 15 min a day for 5 consecutive days each week. All participants were assessed using the Fatigue Severity Scale (FSS), Short Form 36 Vitality Subscale (SF-36) and Dermatology Life Quality Index (DLQI). Serum samples were taken to measure the levels of tryptophan, kynurenine, kynurenic acid, quinolinic acid and serotonin before and after irradiation. Results: Irradiation with blue light resulted in a significant decrease in FSS and DLQI as well as in an increase in SF-36 and serum levels of tryptophan, kynurenine and serotonin. Conclusions: Our study shows that blue light therapy could be used as adjunctive treatment of fatigue and provide an opportunity for further scientific inquiries.